Sanding machine



Jan?. 21, 1941- c. l.. MATTISON y.

` SANDING MACHINE Filed aan. 7, 1959 2 Sheets-Sheet 1 Q w 5 V M v v .S Q w N ,n M, o .v s/ W w W. a ,m mvv MN Sw W MM QW om uw w Gm QN oh L uw 2 m a l* f mw, y Q L 1 m C l um om i n@ Patented Jan. 21, 1941 2,229,466

UNITED STATES PATENT OFFICE SAN DING MACHINE Carl Lawrence Mattison, Rockford, Ill., assigner to Mattison Machine Works, Rockford, Ill., a corporation of Illinois Application January 7, 1939, Serial No. 249,715

4 Claims. (Cl. 51-135) The invention relates to sanding machines and IU and the power driven sanding belts II and I2 more particularly Ito those utilizing endless are selectively pressed into engagement with the abrasive belts. exposed top surface of the work by a stroking y One object of the invention is to provide a shoe I4. This shoe is mounted on ahorizontally 5f sander of the above character in which the belt slidable carriage I5 as will hereinafter appear 5 ysupporting pulleys are supported in a novel manin greater detail so that the shoe may be stroked ner permitting of ready removal and replacement horizontally along the belts to sand the work of the beltl or belts. pieces throughout their lengths.

Another object of the invention is to provide Proceeding now to a more detailed considera- 1'0 a sander of the character described embodying tion, the particular machine illustrated embodies 1o an improved supporting structure for the stroking a supporting structure (Figs. 1 and 2) made up shoe which overlies the belt or belts, such that of a pair of upright pedestals I6 and II bolted to the shoe may be shifted by readily manipulable a horizontal base frame I8. Fixed to the upper means in a direction transversely of the belts ends of the pedestals I6 and II are Dads or while being retained in position on a strong rigid brackets I9 and 20, respectively, which carry the 15 support that has no tendency to buckle or twist. sanding belt electric 4driving motors 2I and 22.

A further object of .the invention is to provide These brackets I9 and 20 are formed as extenin a machine of the character described a novel sions on the opposite ends of a horizontal beam form of actuator for adjusting the position of the or bridge 23, Which J'oins the upper ends of the @stroking shoe, transversely of the sanding belt, pedestals I6 and I'I. The motor 2| is fixed in or belts, such that the operator can readily actuposition on its pad 20, While the other motor 22 ate the same from any point along the machine. iS adjustably mounted in a manner and for a Y Still another object of the invention is to propurpose Which Will hereinafter be eXplaned. vide a stroke sander which, through the pro- In order to accommodate vertical adjustment 25 vision of various structural improvements and of the Work table I0, it is carried by a pair of 25 simplifications, is rendered economical to build Saddles 24 (Figs 1 and 2), WhCh are Vertcally as well as rugged in construction and eifective in slidable `on ways 25, fashioned on the opposed operation. inner `faces of the base pedestals I6 and II. A Further objects and advantages of the inventraveling nut 26 (Fig. 5) is ixed to each of these aotion will become apparent as the following desaddles andvis threaded on a corresponding lead scription proceeds, taken in connection with the screw 21 housed within .the hollow pedestals. accompanying drawings in which- Upon rotation of the lead screws 2'I by a suitable Figures 1 and 2 are respectively front and rear hand crank or the like (not shown), which is conperspective views of a stroke sander embodying nected thereto through bevel gears 28 and an the invention. interconnecting horizontal shaft 29, the table I0 5 Figs. 3 .and 4 are fragmentary plan views 0f is raised or lowered to adjust its position with opposite end portions of Ithe machine shown in respect to the lower reaches of the sanding belts Fig. 1, the guard structure at the top of the ma- II and I2.

chine being broken away and portions of the Provision is also made for horizontal sliding machine being shown in section. movement of the work table IIJ. For this purpose 40 Fig. 5 is a vertical sectional view along the the table is mounted on suitable ball bearing line 5-5 inFig. 3. rollers for sliding movement along horizontal For purposes of illustration and explanation tracks 30 (Figs. 1 and 2) carried by the saddles of its various novel features, the invention has 24. Stops Slia at the ends of the tracks 30 limit been shown herein (see Fig. 1) as embodied in the outward and inward movement of the table. a stroke sander adapted for finishing all manner An elongated handle or bar 3| (Fig. 1) is seof wooden composition or metallic flat work such, cured to the forward edge of the table adjacent for example, as veneered panels, table tops, doors, its left end (as viewed from the front) which fixtures and other similar parts. In brief, this may be readily grasped by the operator to push sander embodies a horizontal work table I0 across or pull the table horizontally into the desired pothe top of which extend the lower reaches of a sition. In this connection it should be noted that pair of endless sanding belts II and I2 respecall of the controls for the machine are grouped tively supported by pairs of pulleys 32-33 and at the left end of the machine and so that they 34-3'5'and driven in the same or opposite direcare readily accessible without walking back and tions. The 4.work pieces are placed on the table forth from one end of the machine to the other. 55v

In accordance with one aspect of the invention,

a novel arrangement has been provided for supporting the belt pulleys 32 to 35 so that the belts can be quickly and conveniently replaced without interference by the pulley supports or the necessity of shifting or removing any of the parts. To this end, the belt pulleys are carried by shafts which are journaled in bearings disposed on opposite sides of the two belts and the bearings on the side opposite the motors are mounted on the ends by outboard supports projecting through the belts so that the entire bearings and their supporting structures are disposed within the paths of travel of the belts. In the particular construction shown, the pulley 33 for the front belt II is fast on the shaft 36 (Fig. 4) of the motor 2l which shaft projects through the rear belt I2 and through the medium of an antifriction bearing 3l loosely supports the pulley 35 of the rear belt. The outer end of the shaft 36 is journaled in an outboard bearing 39 on the short leg of an L-shaped bracket 4I disposed horizontally with its long leg extending through the reaches of the two belts. At its rear end, the bracket is fastened as by bolts 4Ia to the bridge member 23.

At the left hand end of the machine (Fig. 3), the pulley 34 of the rear belt is fast on the short shaft 38 of the motor 22. Alined with the shaft is a shaft 33a journaled in a single bearing 40 and supporting the idler pulley 32. The bearing is mounted on an L-shaped bracket 42 projecting through the belts alongside the pulleys 32 and 34 with its rear end secured as by bolts 42a to the bridge 23. By mounting the pulleys 32 and 34 on the separate shafts 38 and 38a, the belts may betensioned individually and the angular position of the shafts adjusted to obtain correct alinernent of the individual belts.

By placing the brackets 4I and 42 between the upper and lower reaches of the belts Il and I2, the outboard bearings of the pulley shafts 36 and ,38,a are mounted in such manner that the belts maybe removed and replaced without dis- `45 assembly of the supporting structure. For example, if it is desired to remove one or both of the belts II or I2, it is only necessary to relieve the` tension therein by a suitable mechanism hereinafter described, and by then pullingv the 50 belts `forwardly off of the pulleys. This ease of belt replacement is an important factor since the time required for replacement of belts represents idle time for the machine and unproductive time for the workmen. 55 In order to tension the sanding belt I2, the motor 22 is carried by an adjustable support so that the pulley 34 can be shifted toward or away from the belt loops which embrace them. In particular, the motor 22 is Xed to a supporting plate 43 (Fig. 3) which is carried on an underlying plate 43a (Fig. 5) that is slidable upon a pair of ways 44 fashioned on the bracket 20. A screw 45 journaled in the bracket 2li and threaded in a fixed nut (not shown) fast on the lower base plate 43a serves to shift the latter along the ways 44. in a direction longitudinally of the belt I2. To permit of adjustment of the belt I I, the bearing 4,0 of the shaft 38a is similarly mounted through the medium of a plate 48. The latter is supported on an underlying plate 48a which is slidable along ways 49 on the short leg of the L-shaped bracket 42 the adjustment being effected'by turning a screw 5i). A single removable handle 53. may be utilized to rotate either of the 75 lead. screws 45 and 50.

lock the plates 43 and 48 in position. When the sanding belts Iii-I I are under tension, it is merely necessary to revolve the lead screws and`50 by the crank 53 to relieve the tension in the belts for removal of the latter in the manner previously described.

Maximum rigidity of support for the stroking shoe I4 is insured by retaining a xed fulcrum point for it on the carriage I5. It is, of course, necessary to shift the stroking shoe I4 transversely of the sanding belts so that it overlies one belt or the other but in the present improved arrangement the entire supporting structure for the shoe including the carriage I5 and trackway for the carriage is also shifted simultaneously with the shoe during this adjustment. As a consequence, it is unnecessary to project the shoe forwardly from the carriage on a long and relatively unstable support. The trackway for the carriage I5 has been shown herein (Figs. 1, 2 and 3) as embodying a horizontal bar 54 fixed to the forward ends of a pair of projectible arms 55 and an intermediate projectible arm 5`I (Figs. 3 and 5) which are respectively confined for longitudinal movement by overlying brackets 56 and guide plates 58 bolted to the top of the bridge 23. By the use of the arms 55 and 57 the track bar 54 is always rigidly supported, even when in its fully projected or extreme forward position.

The carriage I5 embraces the trackway bar 54 (Fig. 5) being generally C-shaped in cross section.v The carriage is slidably supported on the trackway by rollers having suitable ball bearings to insure smooth, easy movement. Stop blocks, 59 (Fig. l) are releasably clamped on the trackway bar 54 to limit the path of travel of the stroking shoe carriage I5. These stop blocks may be adjusted to any desired point along the trackway bar so that the path of travel of the carriage will conform to the length of the work piece.

Depression of the stroking shoe I4 into working position is accomplished by a forwardly projecting hand lever Ell (Figs. l, 3 and 5) which is fashioned in the form of an extension bolted to,

the outer end of a channel, shaped lever 6I pivoted or fulcrumed by a pin 52 (Fig. 5) to the lower side of the carriage I5. 'Ihe fulcrum or pivot point 62 for the lever El is located on the carriage I5 directly below the trackway bar 54, while the shoe I4 is connected by universa1 joint 63 to the depending end of a vertical link (i4A pivoted toY an intermediate portion of the lever 6I by a pin 55. By virtue of this arrangement the reaction thrust on thepivot 62, incident to a depression of the shoe I4, is transmitted directly upward tothe trackway bar 54. Consequently, there is no tendency for this force to cause any skewing or turning of the carriage I5` about the longitudinal axis of the trackway bar 54. Furthermore this same solid supporting arrangement for the shoe I4 is maintained, no matter what the transverse position of the shoe. I4 may be, since changes in the transverse position of theV shoeare` accomplished by shifting the trackthe bar.

way bar 54 itself, rather than by shifting the shoe with respect to the trackway bar.

In order to maintain the stroking shoe M in an elevated position while it is idle, the upper end of the vertical link 64 is connected by a pivoted cross link 66 with the topof the carriage l5, so as to complete a parallelogram linkage (Fig. A helical compression spring 6l is interposed between L-shaped brackets 68 and 69, which are xedrespectively to the carriage I5 and to the vertical link G4. Consequently the spring 61 urges the link 64 and attached shoe I4 upwardly to an elevated position.

In order to shift the trackway bar 54 transversely of the sanding belts I I `and l2, and thereby correspondingly adjust the position of the stroking shoe I4, a suitable actuating mechanism is provided for projecting or retracting the track bar supporting arms 55 and 51. As shown herein (Figs. 3 and 5), this actuating mechanism includes a bell crank lever pivoted at 'II on the bridge 23 and having a lost motion connection with the trackway Supporting arm 5l. This lost motion connection is formed by a pin 'I2 fixed on the arm 5l and projecting through a longitudinal slot 'I3 in one arm of the bell crank 1D. The other arm of the bell crank projects forwardly and is bent upwardly to clear the track bar 54 and carriage I5. The forward end of this second bell crank arm is connected by a pivot pin 'I4 with a handle or bar I5 which extends along the front of the machine. The opposite end portion of this bar 'i5 is supported by a link 'I6 (Fig. 2) pivotally connected to the bridge 23 and to Accordingly, when the operator wishes to shift the trackway bar 54 forwardly he has but to push the actuator bar 'I5 to the left (as viewed in Fig. 3) and similarly to thrust the bar 'I5 to the right to retract the trackway bar 51?.. Since the actuating mechanism includes a long actuator handle or bar 'I5 extending throughout a major portion of the length of the machine the operator can readily alter the position of the trackway bar 54 when he is standing at almost any point in iront of the apparatus.

Elimination of any tendency of the sanding belts i I and l2 to draw the stroking shoe forward, when stroking in the direction of belt travel, is insured by the use of stationary flexible guard strips Tl and 'I8 (Figs. 1 and 3) made of canvas or the like and stretched over the top of the lower reaches of the belts Il and I2, respectively. The right hand ends of the guard strips l-8 (as viewed from the front of the machine) are xed to pins 'I9 and 80, respectively, while at the opposite end of the machine the strips are secured to a rotatable tension roller 8l. The lower sides of the guard strips 1I--18, which contact the sanding belts Il and l2, are preferably given a coating of anti-friction material such as graphite. With the strip arrangement described the stroking shoe I4 presses on the strips il or 'I8 rather than directly on the belts, with the result that the same operating control is achieved when stroking in either direction.

The upper reaches of the sanding belts II and I2 are received within a channel shaped sheet metal guard 32 (Figs. 1, 2 and 5). This guard receives the dust carried from the work by the belts and also prevents the belts from flying out and striking the workman in the event of breakage. The opposite ends of the guard 82 communicate with sheet metal hoods 83 and 84 which may be connected to suitable exhaust fans (not shown).

Preferably, though not necessarily, the electric driving motors 2i and 22 are reversible and may be started in either direction or stopped by suitable push button switches 85 (Fig. 1) provided at the left end of the machine. By utilizing two sanding belts driven by independent reversible motors the machine may be adapted for various applications. For example, one sanding belt may be provided with coarse grit and the other with iine grit for nishing.. With such an arrangement tape, glue and the like may be removed from veneered stock by the coarse belt and the fine belt then used to nish the job without removing the work from the machine or changing the belts. On the other hand, in soine types of wood the grain has a tendency to raise when polished, rendering it desirable to sand the piece in opposite directions. This can be accomplished by properly controlling the direction of the sanding belts II and l2. When constant running of the belts in one direction dulls the abrasive grit to the point of inefficiency the belts can be run in the opposite direction by reversing the motors, thus exposing additional sharp edges in the grit so as to achieve greater belt life.

In the operation of the machine described above the operator grasps the work table handle 3l and pulls the table out so that it is exposed to receive the Work. The work piece is then laid on top of the table and the height of the table adjusted to accommodate the thickness of the particular work piece, whereupon the table is thrust back intoI operating position with the work piece located below the sanding belts Il and I2. The electric driving motors 2| and 22 are started to drive the belts in the desired directions by the push button switches 85, the direction of the belt travel selected being dependent upon the character of the work to be performed, as outlined above. The stroking shoe I4 may then be located over one or the other of the belts I I or I2 by shifting the actuator bar l5. The stop blocks 59 are set for the length of stroke desired. Then, nally, the operator pushes down on the shoe hand lever 60 to depress the shoe into contact with the 'guard strips il or 'I8 and the shoe is stroked back and forth by pulling and pushing on the lever 60 in a horizontal direction so as to stroke the shoe back and forth across the top of the work piece in the usual manner.

Changing or replacing the sanding belts II and l2 is readily accomplished by simply opening doors on the dust guards 83 and 84, and then slacking off the belts by turning the lead screws l5 or 55 (Fig. 3) so as to shift the motor shaft 38 or the shaft 38a toward the body of the machine. Thereafter the sanding belts can be readily pulled forward off of their supporting pulleys and without any interference from the supporting structure of the pulleys since the brackets il and 42 extend between, rather than around, the upper and lower reaches of the belts.

Although a particular embodiment of the invention has been shown and described, in some detail for purposes of illustration and explanation there is no intention to thereby limit the invention to such embodiment but on the other hand the appended claims are intended to cover all modications and alternative constructions falling within the spirit and scope of the invention.

I claim as my invention:

l. A dual belt sander comprising,A in combination, a horizontal work table, a pair of endless sanding belts disposed side by side with their lower reachesoverlying said table and with their upper reaches substantially paralleling the lower reaches in spaced relation above the same, each of. said belts being provided with two supportingpulleys over which they are led with the pulleys disposed in the loops at the opposite ends of the belt reaches and with the pulleys at each end of the belts arranged coaxially, independent means .disposed on the same side of said belts and arranged to drive the pulleys of the respective belts, a irstV shaft driven by one of said driving means and projecting through the pulleys of one pair, said shaft loosely supporting the pulley adjacent the driving means and being coupled to the remote pulley, second and third shafts alined with each other and respectively supporting the pulleys of the other pair, one of said latter shafts being driven by one of said driving means, a bracket rigidly sup-ported on the same side of saidl belts as said driving means and projecting between the upper and lower reaches of the belts, and a bearing on the free end of said bracket supporting the end remote from said driving means oi the outermost one of said second and third shafts. i

2. A double belt sander having, in combination, a pair of endlessl abrasive belts disposed side by side, two pairs of drive and idler pulleys supporting opposite ends of said belts, a shaft supporting one pair of said pulleys and coupled to the driving pulley of said pair, an electric motor at one end of said belts driving said shaft, two shafts supporting the other driving and idler pulleys and individually mounted for movement longitudinally of the associated belt and also to swivel about an axis extending transversely of the pulley axis, an electric motor at the other ends of the, said belts disposed on the same side of the belts as said rst motor and driving the shaft of said other driving pulley, and bearing supports for the outer end of said rst shaft and for said other idler pulley comprising brackets extending through said belts and supported adjacent said motors.

3. A sander comprising, in combination, a horizontal work table, a sanding belt having a reach overlying said table, a horizontal trackway extending alo-ng and above said belt reach, means supporting said trackway for bodily adjustment transversely of said'belt reach, a stroking shoe, means including a carriage traversable along said trackway for supporting said stroking shoe above said belt. reach, and means including an elongated and endwise shiftable actuator lying along thel front of the sander for adjusting the position of said trackway bar transversely of said belt reach.

4. A sander comprising, in combination, a horizontal Worktable, a sanding belt having a reach overlying said table, a horizontal trackway extending along and above said belt reach, means supporting said trackway for bodily adjustment transversely of said lbelt reach, 1a stroking shoe, means including a carriage traversable along said trackway for supporting said stroking shoe above said belt reach, an elongated and endwise shiftable actuator bar lying along the front of the sander, and means including a bell crank lever pivotally connected at its opposite ends to said trackway and to said bar for Aoperatively connecting the same to effect transversey adjustment of said trackway in response to endwise movement of said actuator bar.

CARL LANRENCE MATTISON. 

